The Development of Fe[sub.3]O[sub.4]-Monolithic Resorcinol-Formaldehyde Carbon Xerogels Using Ultrasonic-Assisted Synthesis for Arsenic Removal of Drinking Water

• Published in: Gels Vol. 9; no. 8
• Main Authors: Khamkure, Sasirot, Gamero-Melo, Prócoro, Garrido-Hoyos, Sofía Esperanza, Reyes-Rosas, Audberto, Pacheco-Catalán, Daniella-Esperanza, López-Martínez, Arely Monserrat
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.07.2023
• Subjects: Aquifers; Arsenic; Drinking water; Formaldehyde; Water, Underground; Mexico; Germany
• DOI: 10.3390/gels9080618
• ISSN: 2310-2861

Inorganic arsenic in drinking water from groundwater sources is one of the potential causes of arsenic-contaminated environments, and it is highly toxic to human health even at low concentrations. The purpose of this study was to develop a magnetic adsorbent capable of removing arsenic from water. Fe[sub.3]O[sub.4]-monolithic resorcinol-formaldehyde carbon xerogels are a type of porous material that forms when resorcinol and formaldehyde (RF) react to form a polymer network, which is then cross-linked with magnetite. Sonication-assisted direct and indirect methods were investigated for loading Fe[sub.3]O[sub.4] and achieving optimal mixing and dispersion of Fe[sub.3]O[sub.4] in the RF solution. Variations of the molar ratios of the catalyst (R/C = 50, 100, 150, and 200), water (R/W = 0.04 and 0.05), and Fe[sub.3]O[sub.4] (M/R = 0.01, 0.03, 0.05, 0.1, 0.15, and 0.2), and thermal treatment were applied to evaluate their textural properties and adsorption capacities. Magnetic carbon xerogel monoliths (MXRF600) using indirect sonication were pyrolyzed at 600 °C for 6 h with a nitrogen gas flow in the tube furnace. Nanoporous carbon xerogels with a high surface area (292 m[sup.2]/g) and magnetic properties were obtained. The maximum monolayer adsorption capacity of As(III) and As(V) was 694.3 µg/g and 1720.3 µg/g, respectively. The incorporation of magnetite in the xerogel structure was physical, without participation in the polycondensation reaction, as confirmed by XRD, FTIR, and SEM analysis. Therefore, Fe[sub.3]O[sub.4]-monolithic resorcinol-formaldehyde carbon xerogels were developed as a potential adsorbent for the effective removal of arsenic with low and high ranges of As(III) and As(V) concentrations from groundwater.